CONTROLLING A FLUID TREATMENT SYSTEM

A fluid treatment system includes an apparatus(1) provided with an inlet(3)for receiving a fluid to be treated, an outlet(4)for providing at least partially treated fluid and an interface for receiving a replaceable fluid treatment cartridge (2)including at least one fluid treatment part(10,11) for treating fluid led through the fluid treatment part(10). A Method of controlling the fluid treatment system includes obtaining a target value as input. A fraction of fluid led through at least a certain one(10)of the at least one fluid treatment parts(10,11)in a mix of fluid further including fluid led from the inlet(3)to the outlet(4)so as to bypass at least the certain fluid treatment part(10) is caused to be adjusted. The step(26)of obtaining a target value as input includes obtaining data from a machine-readable tag(23) with which the cartridge(2) is provided.